Joining LINX requires paperwork, connecting a router, and connecting to route servers. However, peering with the 356 LINX members is not straightforward and requires contacting each NOC individually. Determining who to peer with depends on analyzing traffic data using tools like traceroute, NetFlow, and the AS-STATS collector. AS-STATS collects and analyzes NetFlow/sFlow data to identify the top sources and destinations of traffic to help members determine which peers matter most.

1. AS-STATS
GET THE MOST OUT OF LINX
Thomas Mangin
Exa Networks Limited
LINX 69

2. Joining LINX, an easy process ?
● Fill the paperwork
● Plug in the router
● Connect to the route servers
● Some members stop here !
● …
● PROFIT :D

3. Joining LINX, not an easy process ?
● Emailing the linx members
● 356 NOCs to contact
● with many different peering policies
● with many unresponsive peering coordinators
● No one wants to send 300+ peering requests
● No automation (roll your own)
● Benefits are unclear
● Is it worth the effort ?

4. Who will peer with you ?
?

5. Who will peer with you ?
Free beer for you tonight if you answered
"Patrick W. Gilmore"
But it is not the right answer

6. Who will peer with you ?
● Guess work !
● You are the new kid on the switch
● You are kind of expected to make the first move

7. Who will peer with you ?
● The content networks
● Akamai, Yahoo, Microsoft, Google, Facebook
● all have « open » peering policies
● Linx members with an open peering policy
● http://peeringdb.com/
● Generally small/medium networks
● You want them as peers but are they a priority ?
● People seeing you via transit

8. Who should you peer with ?
● Networks you see via transit
● Everyone if it is your first IX
● Otherwise not as clear
● Networks you send/receive the most trafic to

9. How to find those « good » peers ?
● Look at traces between your networks
● routers with full routing tables can display ASN
traceroute / traceroute as-number-lookup
● http://oppleman.com/dl/?file=lft-2.3.tar.gz
use whois.ra.net to find the hops' ASN
● Use netflow to find out who matters to you
● Can Linx do more to help ?
● Web tools to help you find and contact peers
● Possibly – if you think it is important : tell them !

10. What is NetFlow ?
● A protocol defined by RFC 3954

11. What is NetFlow ?
● A protocol defined by RFC 3954
● Not helpful !
● A way to know what trafic your router is forwarding
● generating UDP packets
● can include SRC/DST ASN of the packet

12. Where to use NetFlow ?
● Configure it on your EBGP peers
● transit AND peering
● with a full routing table
● Do not need an high sampling rate
● you care about your TOP speakers
● save yourself some router CPU cycles

13. NetFlow collectors
● Many exist
● http://www.networkuptime.com/tools/netflow/
● Missing my favorite : as-stats
● https://neon1.net/as-stats/
● Last changelog shows two LINX members :D
● accept sflow as well (foundry users rejoice !)
● Install it in one hour if you can use linux/*BSD
● … or two during the meeting today
● someone else to do a demo later on ?

14. AS-STATS
● A netflow/sflow collector
● Storing data in RRD files
● A cron program
● order the ASNs by level of trafic exchanged
● A web interface to :
● See your trafic per ASN
● See your trafic per LINK

15. How as-stats look ? peers

16. How as-stats looks ? link

17. AS-STATS (configuration)
# Router IP
# SNMP ifindex of the interface monitored
# tag (used by RRD)
# description (displaid on the web page)
# color in HEX RGB
192.0.2.1 10 linx LINX 0A8474
192.0.2.1 40 transit T1 4E66A1
# find your router interface SNMP ifindex
# show snmp mib ifmib ifindex | include Ethernet
# show interfaces | match "SNMP ifIndex"

18. AS-STATS (daemon)
● an example of a supervise script (for djb fans)
#!/bin/sh
exec
setuidgid nobody
/opt/as-stats/bin/netflow-asstatd.pl
-s 1000
-r /srv/as-stats/rrd
-k /opt/as-stats/conf/netflow-knownlinks

19. AS-STATS (daemon)
● Reflect the locations you use in the program
/* changes these values to suit your local configuration */
$rrdpath = "/srv/as-stats/rrd";
$daystatsfile = "/srv/as-stats/txt/asstats_day.txt";
$rrdtool = "/usr/bin/rrdtool";
$asinfofile = "asinfo.txt";
$knownlinksfile = "/opt/as-stats/conf/netflow-knownlinks";
$outispositive = false;

20. AS-STATS (cron)
● cron.d/as-stats (runs hourly)
00 */1 * * * nobody
/opt/as-stats/bin/rrd-extractstats.pl
/srv/as-stats/rrd/
/opt/as-stats/conf/netflow-knownlinks
/srv/as-stats/txt/asstats_day.txt

21. AS-STATS (apache)
<VirtualHost 192.0.2.123:80>
ServerName flow.domain.com
DocumentRoot /opt/as-stats/www
<Directory /opt/as-stats/www/>
Options Indexes FollowSymLinks MultiViews
AllowOverride All
</Directory>
</VirtualHost>
Check file permissions, but – that's it !

22. Example (one way to do on Cisco)
ip cef
flow-sampler sampler-1000
mode random one-out-of 1000
interface GigabitEthernet0/1
ip address 195.66.224.235 255.255.254.0
no ip route-cache flow
no ip route-cache cef
no ip flow ingress
flow-sampler sampler-1000
flow-sampler sampler-1000 egress
interface Loopback 0
ip address 192.0.2.1 255.255.255.255

23. Example (Cisco cont.)
ip flow-cache timeout active 5
ip flow-export version 5 origin-as
ip flow-export destination 192.0.2.123
ip flow-export source loopback 0
ip flow-aggregation cache as
cache timeout active 5
export destination 192.0.2.123 9000
enabled

24. Example (Juniper)
> show interfaces ge-0/3/0 unit 123
description Linx;
vlan-id 123;
family inet {
mtu 1500;
address 195.66.224.235/23;
sampling {
input;
output;
}
}
/* http://thomas.mangin.com/#tag:link_ipv6_on_juniper */
family inet6 {
mtu 1500;
address 2001:7F8:4::7814:1/64;
}

25. Example (Juniper cont.)
> show configuration forwarding-options
sampling {
input {
family inet {
rate 1000;
max-packets-per-second 7000;
}
}
output {
cflowd 192.0.2.123 {
port 9000;
source-address 192.0.2.1;
version 8;
aggregation {
autonomous-system;
}
}
}
}

26. More information
https://neon1.net/as-stats/as-stats-presentation-swinog16.pdf
http://www.netflow-analyser.co.uk/scrutinizer-netflow-sflow-analyser/support/activating-netflow.php
http://netflow.caligare.com/
http://www.cisco.com/en/US/docs/routers/7600/ios/12.2SXF/configuration/guide/nde.html
http://puck.nether.net/pipermail/cisco-nsp/2007-February/038498.html
Questions ?